Particular, Not Pretentious

How to Make Clear Ice At Home – The Best Cocktail Ice Molds for Crystal Clear Results

How to Make Clear Ice

I’ve read dozens of articles explaining how to make clear ice. Some articles will claim that you have to use distilled water to get clear ice, while others claim that it can be tap water as long as you boil it twice. In addition to the various water types there are numerous ice molds available, most with corresponding marketing materials showing perfectly crystal clear ice. [2018 Update: Many new molds are coming out, so please subscribe to the email list to know how these molds perform. I’m really intrigued by the recent Wintersmith’s Kickstarter] Since the dawn of the cocktail renaissance, enthusiasts have lusted after the beautifully cut, clear cubes adorning their old fashioneds and sazeracs at craft cocktail bars. Whether you’re new to cocktails or a longtime enthusiast, by the time you finish reading this post you’ll have a better grasp of the how clear ice is made, options for making clear ice at home, as well as one of the best visual illustrations of the process I’ve ever seen. The same process used to create clear ice can even be adapted to freeze flowers, mint, and other garnishes inside.

Cocktail Inception: The cocktail that is on top of the iPhone is the same cocktail featured on the iPhone screen, as viewed through crystal clear ice.

There are a few reasons that clear ice is desirable, and I’d argue that the largest reason is simply aesthetics. A cocktail with a large clear ice cube or several smaller clear ones is more appealing than cloudy ice. One frequently mentioned point is that larger ice cubes will dilute drinks slower than smaller and more imperfect ones due to having less surface area, but this is only a partial truth. The reason that smaller pieces of ice appear to dilute a drink faster is because there is more liquid water on the surface of the ice. The ice itself has no more or no less chilling power, but ice with greater surface area will bring a drink to equilibrium faster.

The commonly suggested methods for making clear ice at home are full of partial truths, and will never allow you to create clear cocktail ice like you’ll find in bars with ice programs. To understand the reason for this, it’s important to understand some of the unique properties of water. First and foremost, the property of water that enables the process of creating clear ice is known as the “anomalous expansion of water”. This simply means that water is an anomaly in that it expands rather than contracts when freezing. Anyone who has put a bottle of water (or worse, soda or beer) in the freezer and forgotten about it has experienced this phenomena in an unpleasant way. This is because water expands in volume by around 9% when it goes from a liquid to a solid.

To better understand what makes clear ice, we need look no further than nature and the way lake water freezes. The water in a lake is insulated by the earth on all sides except for the surface where it can begin to cool. Water is most dense at around 4° C, but once the surface drops to 0° C it can begin to freeze. Water will supercool to 0° C or colder, but wont’ begin to freeze unless ice crystals are already present or there is an impurity for the crystals to begin to form on. Since ice is less dense than liquid water, it floats on the surface of the lake and the impurities are forced downward with the denser water. Not only does this particular process facilitate the creation of clear ice, but the speed at which the water freezes plays an important role. This is why boiling water can improve the clarity of ice – because the water is still warm and will take longer to freeze. Boiling the water will also release trapped gases, but not enough to make crystal clear ice. The more important factor is being able to slowly control the direction of the freeze so that the impurities have a place to go besides the center of the mass. When freezing slowly, ice crystals force the impurities away, but if freezing occurs quickly these impurities can become trapped, resulting in cloudy and cracked ice.

It’s no fun to freeze flowers in ice cubes if the ice isn’t clear!

For commercial-grade ice used in restaurants, bars, and ice sculptures, the Clinebell machine is the standard. This machine slowly freezes the water while simultaneously circulating it. The result is that all the impurities are forced out and you are left with a crystal clear 300 pound block of ice. This is great if you have $5,500 dollars for a Clinebell, a way to hoist out the ice, and then a place to store it. Let’s not forget a chainsaw to cut the block down into manageable sizes. Luckily, there are more practical methods for home enthusiasts, each of which have varying degrees of quality.

Even though this topic has been tested by numerous individuals (most exhaustively by Camper English), I needed to conduct the experiments for myself and add one more element. I gathered up the numerous ice molds and trays that I’ve accumulated over the years, which included those by Tovolo, OXO, Dexas, and True Cubes. I also conducted some tests with the directional “cooler method”, but discontinued that particular method as the results were the same as using the True Cubes mold (also directional), and because freezing each large block of ice takes at least 3 days, plus the time to hand-cut the cubes.

These hand-cut cubes were made with directional freezing in an Igloo cooler.

I tested both cold and hot versions of tap water, purified bottled water, Brita filtered water, distilled water, and alkaline water with trace minerals. My process for the hot water was to boil it, then let it cool slightly before putting it into the molds and freezing it. While I was thorough with the process, there are additional variables to consider such as the humidity, temperature of the freezer, temperature of the container, and temperature of the water when it was placed in the freezer. These are variables that I did not measure or control, and, unless you are Dave Arnold, I doubt you would either. After all, this guide is for enthusiasts looking for a practical way to get clear cocktail ice without having to operate a small laboratory. It’s simply not practical to measure all these variables every time I want to make ice. In other words, I subscribe to the method that Tim Ferriss touts as the “minimum effective dose”. There is a point of diminishing returns, and I’d rather be enjoying cocktails with company than cutting ice.

The Contenders – An Ice Mold Review

Here are the quick stats on the various molds I used in the tests. There are a few other molds out there that I discovered in my research, and they are linked at the end of this post. It’s noteworthy that Tovolo has stepped up their game and created some insulated molds. (Linked at the end of the post too.) If you want to specifically make ice spheres, I’d suggest you check out their mold or better yet, the sphere maker from Cocktail Kingdom.

Description: A traditional style ice cube tray, which creates 14 pieces of crescent-shaped ice. The design makes it very simple to remove ice from the tray and the sliding cover helps protect the ice from getting a freezer burned flavor. This is my preferred method for creating cocktail shaker ice.

Description: I tested two Tovolo ice molds, the sphere and the cube. They both work the same way. There is a solid plastic base with a fill line. There is a cap made of silicone that slides on top and inside of the base.

Description: This is one of the newer systems that offers directional freezing. This system has three pieces – an insulated portion, a silicone reservoir, and a silicone insert that fit inside the larger reservoir. This system creates 4 cubes in the top tray, while the cloudy ice forms in the lower region and is discarded.

Price: $39.87

Ice Size: 2″

“Cooler Method”

Description: This is the directional freezing method devised by Camper English. This “hack” uses a small cooler with the lid removed to facilitate directional freezing. It has been my preferred method for “presentation ice” for over a year, and has been the only way I’ve been able to achieve perfect ice. The downside is the amount of time involved. It takes 2-3 days for the large quantity of ice to freeze, then it takes at least another hour to cut down the ice once you include time for allowing it to temper. If you don’t let the cooler freeze all the way, there should be minimal cloudiness to cut off. If it does freeze completely, simply cut off the cloudy portion. While this method does take time, it consistently has produced great results. However, it’s a rare person that is willing to spend the time required to create clear ice with this method.

Price: ~$30 (you’ll need a cooler, a bread knife; a wooden mallet and ice pick are good additions too)

Ice Size: One benefit to this method is that you choose the size. If you’re willing to spend the time, you can make whatever size of ice cube you need.

This ice is the result of directional freezing. This ice is on its side, with the cloudy portion being from the bottom of the cooler.

The Visual Results Based on Water Type

As previously mentioned, the freezing method has a greater impact on the clarity of the ice than the type or temperature of water. For methods that include standard molds the freezing effect is so isolated to that particular portion of the mold that it becomes difficult to discern the results – cloudiness, gas streaks, cracks in the ice will all be present in every cube. For the breakdown below I’ll show reference from each mold, but base the primary analysis on the results of directional freezing from the cooler method or the True Cube system.

Typical ice mold results.

There are a lot of reference shots, and they get a bit redundant, so click on any of the thumbnails below to view the gallery. Otherwise, read the summaries and make the white negroni featured at the end of this post.

Brita – Surprisingly, this method produced a fair amount of gas bubbles. The only method that created more was distilled water. Brita (Boiled) – There were still some gas bubbles in this sample, but there were less than in the standard Brita sample.

Distilled – This method had the most gas streaks.The result wasn’t cloudy, but it was littered with the longest gas bubble streaks across the entire cube.Distilled (Boiled) – Better than standard distilled water, but not great. The Tovolo Cube mold showed one of the craziest streak patterns with this water type.

Purified – This produced the most cloudy result of any method. There weren’t really any gas streaks, but there was concentrated cloudiness in the center of the cube.Purified (Boiled) – As was the norm in all methods, boiling this water did reduce the amount of cloudiness.

BLK – This method was one of the clearest. Despite the BLK water literally being black from the fulvic trace minerals, the minerals were for the most part removed from the clear portion of the ice. There were little to no gas bubbles in the ice. The “waste ice” from this sample is stunning and the perfect illustration of how directional freezing works.

The bottle of BLK. water is clear, and on the far right is a glass of it. Through directional freezing, nearly all of the added minerals are removed, creating clear ice.

Both of these cubes started as BLK. Water.

To summarize these visual results, any of these methods will create clear ice that will dazzle 90% of your guests as long as it’s created with a directional freezing method. Distilled water created the most visually distracting cubes, but is still acceptable to the vast majority of the population.

The Taste Test

I collected one sample of each ice type and allowed it to melt in order to give it a taste test. I’d summarize these results by saying, if the water tastes bad when it goes in, it’s going to taste bad when it comes out. The distilled water and the BLK water have a different mouthfeel than the others, and that was preserved. The best advice I’d give to ensure your ice doesn’t develop an off or freezer-burned taste is to make sure you use a quality water source, keep your molds clean and don’t leave them in the freezer when you’re not making ice with them, and make sure your freezer itself doesn’t have any odor issues.

Summary

To summarize the results, the single most important factor in attaining clear ice is that it be done through slow directional freezing. Water type and temperature will have a small impact on clarity, but the greatest impact it will have is that poor quality water will impart any flavors into the drink as it melts. The two obvious winners for attaining clear ice were the True Cubes mold and the “cooler method” since they both employed directional freezing, allowing the impurities to be easily discarded. For either of these methods, the choice in water type or preparation method had little impact on the resulting ice clarity, but will have a flavor impact as it melts. To make clear ice at home, the only worthwhile methods will incorporate directional freezing.

Congratulations! You’ve read this far and clearly (ba-dum-tssh) deserve a cocktail. Why not one that will showcase perfectly clear ice? If you liked this post, or want to see more like it, please give it a share using the buttons at the end of this post! If there is a specific mold I missed, feel free to mention it in the comments, on social media, or via email and I’ll consider adding it to these results. If you’re just getting your home bar set up, don’t miss this guide I put together which contains the basic set of tools you’ll need to get started.

*Disclosure: This review has been on my mind for awhile, and in my research I came across the True Cubes system. They sent me their product to be included in this review. The results do speak for themselves,. Other directional freezing molds may be worth investigating, and that’s why I previously mentioned that Tovolo has released some, as well as the brands listed above in the gear section which include Neat Ice and Wintersmith’s. However, the best tool for getting clear ice at home really isn’t a tool, it’s a method.